Electrical discharge device



Oct. 12 1926.

1 J. H. PAYNE, JR

ELECTRICAL DISCHARGE DEVICE G m a 0 u t e 1 W M I 1 aw mayilllffllll/fl; 7ft

Filed Sept. 50 1922 Psameaoa. 12, 1 926.

UNITED STATES PATENT. o FIc JOHN H. PAYNE, JR, QF BA LLSTON SPA, NEWYORK,

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Application filed September 80, 1922. SerialRo. 591,495. v

The present invention relates tothe construction of electrical dischargedevices of large power, and it is the object of my invention to providea device of such high current-carrying capacity, and of suchruggednessand reliability that it may be employed for transmitting andcontrolling electric currents for industrial purposes. I j

Although the benefits of my invention are not restricted to anyparticular form or type of electrical discharge apparatus, my

invention may be advantageously embodied.

m a high powered discharge device adapted to be controlled by themagnetostrictive effeet: that is, the current-controlling effect of themagnetic field of the heating current traversing the cathode.

As considerable heat is liberated at the anode, or plate, of an electrondischarge device, this electrode in some instances has been constitutedthe container so as to permit of efficient cooling. The cathode wassealed in a glass stem which in turn wassealed to the lip or rim of thecontainer. Although this construction increased the power capacity ofthis class of devices, it was found that other serious limitations wereencountered as the transmitted energy was increased. One limitation-wasimposed by the current-carrying capacity of the conductors which weresealed into glass. Another serious limitation was conditioned by therelative displacement of heavy metal parts when expanding andcontracting over the wide range of temperatures to which electricaldischarge devices are subjected, for example, rupture of seals is likelyto be caused by the expansion at high temperatures of a heavy cathodewhen held in a fixed relation to the container and other parts whichoperate at alower temperature. The difliculty of disassembling a devicein which glass is sealed directly to the electrodes rendered repair ofsuch a device impracticable, or at least very expensive.

In accordance with one of the features of my present invention, I haveprovided an electrical discharge device in which are provided easilydemountable seals for. large, rigid conductors in insulating relation toa metal container. In accordance with another feature of my invention, Iprovide a construction permitting displacement during expansion of theparts of an electrical discharge apparatus while gas-tight andelectrically maintaining the apparatus gas-tight. The above and otherstructural features of my invention, for example, novel cooling arassrenon r0 GENERAL 'ELEcrangements, will be set forth with greaterparticularity in the accompanying claims.

The accompanving: drawing shows in Fig. 1 a lon itudinal sectional'viewof an apparatus em odying my invention; Fig. 2 is a detail view ofaterminal, and Fig. 3 shows somewhat enlarged and partly in section thelower end of the apparatus.

The apparatus shown in Fig. 1 comprises an enclosing tube 1, consistingof copper, or

other suitable metal, joined at opposite ends to glass tubes 2, 3 byconical rings or thimbles 4, 5consisting of' a copper coated alloy ofnickel and iron having a coefiicient of thermal expansion approximatelythat of the adjoining glass; A flux of'borax or the like preferably isprovided on these thimbles when making the seal by fusion of glass.These thimbles 4, 5 are joined to the tube 1 by inserting the rim of thethimbles in a groove in the tube 1, a solder being applied to make atight seal, shown in Fig 3, (as hereinafter described and in connectionwith the junction of parts at the lower end ofthe device).

A rod-like cathode 6 extends axially through the tubular anode 1. Thecathode consists of a suitable refractory metal, for example, tungsten.It is or other convenient way, at opposite ends joined by swaging,

to threaded caps 7 8 of machinable refractory metal, as for example,molybdenum which in turn are screwed, or otherwise inserted, into heavytubular conductors 9, 10, preferably consisting of copper. The enlargements 11, 11 upon the ends of the cathode conductors 9, 10 act asshields .to prevent electrons striking the glass or seals at theextremities of the tube. The narrowness of the space between the shields11, 11 and the tube 1, prevents the entry of an electron discharge.Additional shields 12, 12 preferably are providedbetween the leads 9, 10and the thimbles 4, 5 to completely protect the seals from over-heating.

The tubular cathode conductors 9, 10 are artificiallycooled by water, orother-suitable fluid, supplied respectively by-tubes 13, 14 to theconductor 9 and by tubes 15, 16 to the conductor 10. These tubes projectthrough the terminal caps 17, 18. The respective inlet tube of each setextends into close proximity to the connection of the terminalconductors with the cathode. The ends of the glass tubes 2, 3 are sealedto make a gas-tight closure.

At the upper end of the tube the thimble 19 which is joined to the glasstube 2 by fusion of the glass is also joined by solder (as shown in Fig.3) directly to a conical metal closure 20, which in turn is soldered tothe cathode lead 9. At the lower end of the tube the thimble 21 isjoined by solder to a ring 22 in turn attached to an extensible collar23 consisting of sylphon metal or other suitable material. The diaphragmis joined to a ring 24 fixedly attached to the tube 10. The solder in 22should have a lower melting point than the adjoining parts to permitsoftening the solder by heat when demounting the apparatus. Theextensible crimped metal collar which constitutes part of the enclosingcontainer permits relative displacement of the cathode 6 and the anode 1without injuring the apparatus. A weight or spring 25 may be attached tothe lower end of the cathode conductor 10 to exert traction upon thecathode.

' When the device is suitably supported, the

weight may be hung from the terminal cap 18 thus holding the diaphragmextended to prevent displacement of the parts during operation. Shields26, 26 preferably also may be provided between the thimbles 19,

I 21 and the cathode leads 9, 10 respectively jected to differenttemperatures.

although these shields are not essential.

Externally the anode 1 is surrounded by a jacket 27, convenientlyconsisting of brass, and provided with inlet and outlet tubes 28, 29 forcirculating a cooling fluid in contact with the anode 1. A removableclosure 28' may be provided to permit inspection of the anode 1especially during the preliminary bake-out, when removing gas.Fluid-cooled collars 29', 30 are interposed between the seals 4, 5 andthe anode section and adja cent the current receiving portion of thecathode 6 to permit heating the anode by operating the tube to drive outgas without overheating the seals. An expansible diaphragm 31 isprovided as part of the jacket 27 to permit relative linear displacementof the anode 1 and the jacket 27 when sub- Evacuation of the gas spacewithin the enclosure 1 occursthrough a tube 32 leading to a suitablepump.

An electron discharge may be controlled by a magnetic field generatedbya current traversing one of the electrodes. For example, in theapparatus above described, the magnetic field of the current traversingthe cathode may be used to control the electron current traversing thedevice, commonly known as the space current. When the cathode currentexceeds a critical value the space current decreases and at highercathode currents falls to zero by the choking action of theelectromagnetic field, which is known as the electrostrictive eflect,the relation between the cathode current I, the diameter D, of anenclosing anode. The diameter d of the cathode to the voltage Vimpressed between cathode and the anode at which the reduction of spacecurrent occurs (cut off Voltage) may be expressed as follows;

V= .0188 I (log d In the above described device, extremely high powersof the order of magnitude of 1000 kilowatts may be controlled by theelectrostrictive effect, no auxiliary electrodes being necessary. Forexample, a powerful high frequency current may be produced from a directcurrent, by impressing a high frequency current of half the desiredfrequency upon the cathode by the conductors 33, 34 and connecting thecathode 6 and the anode 1 to a suitable source of direct current by theconductors 33, 35. The connection of conductor 35 to the an- .ode hasmerely been indicated as terminal clamps suitable for this purpose arewell known.

As shown in Fig. 2 the terminals 36, 87 preferably consist of a copperring 38 connected to a split clamp 39 by flexible radial wires 40. Thering 38 engages with a channel in an arc-shaped fixed terminal 41. Firmcontact may be secured by drawing the engaging parts together by boltsfor which the holes have been indicated. This construction permitsmaking a firm electrical contact while still permitting longitudinalmovement of the cathode and provides a low resistance for high frequencycurrents as the skin effect is reduced by radial arrangement of theconductors 40.

\Vhat I claim as new and desire to secure by Letters Patent of theUnited States, is

1. An electrical discharge device comprising an envelope, an electrodesealed therein at regions spaced apart and yielding means constitutingpart of said envelope permitting changes of length of said envelope.

2. An electrical discharge device comprising a cylindrical envelope, anda substantially rigid conductor sealed into opposite ends thereof, saidenvelope consisting in part of yielding material permitting longitudinalexpansion and contraction of said conductor.

3. An electrical discharge device comprising a tubular electrode, alinear electrode axially located within said tubular electrode, ayieldable collar interposed between said electrodes and insulating meansfor completing the enclosure of the space between said electrodes.

4. An electrical discharge device comprisis maintained.

5. An electrical discharge device comprising a linear electrode capableofsupporting an electrical discharge, a cylindrical electrodesurrounding said linear electrode, a-

necting the glass tubes and cylindrical section of insulating materialsealed to said cylindrical electrodeand a yielding linkinterposedbetween said insulating section and said linear electrode and sealedthereto.

6. An electrical discharge device comprising an enclosure, means forsupporting therein an electrical discharge, a second enclosure aboutsaid first enclosure and connected thereto the wall of said secondenclosure in part at least including an extensible portion to permitlongitudinal dis lacement: of said enclosures temperatures. s

7. An electrical discharge device comprising an evacuated vesselconsisting part of metal, glass tubes sealed to opposite ends of saidvessel, an electrode extending through said vessel and rojecting fromthe outer ends of the glass tu es and means c0nsaid electrode, saidmeans including a' crimped extensible collar. I

8. An electrical discharge device com-.

prised-inpart at least of a lass member, a

metal sleeve fusion-sealed into said glass member at one end, and ametal member having a groove engaging with the opposite end of saidsleeve. and a seal of metal-of lower .melting point than said engagingmember making a gas-tight seal at the oint between said members.

' prising cooperating electrodes one of which I consit-utes part of anenclosure forthe other.

9. An electrical. discharge device comprising an enclosure consisting ofa main section of metal joined to terminal zones of glass,. metalmembers sealed to said glass zones, and conductors soldered to saidmetal members.

10. An electrical discharge device comelectrode, means for insulatingsaid electrodes from each other and separate means for sealing said"enclosure by fusion of metal.

11. An electrical discharge device comprising an enclosing envelope, aconductor there- 1n operable at anelevated temfperature and meansexternal to said device or maintaining said conductor taut when heated.

I 12. An electrical discharge devicecompriswhen at di erent meansexternal to. said .trode and seal, said means inc opposite ends of saidanode joined to said iespective cathode conductors, each of saidclosures including an insulatin section and at least one of saidclosures 111C uding an extensible section to permit relative changes oflength of said electrodes to occurwithout injury, an enclosing 'acketmounted upon said anode andjoined t ereto, said jacket also including anextensible section and means for circulating a cooling fluid through thespace between said anode and said jacket.

13; An electrical dischar e d ing a tubular anode, a ro -like cathodeextending therethrough, rigid current-conveying conductors connected too posite ends of said cathode, cylindrical insulating closuresrespectively sealed to opposite ends of said anode, metal membersincluding an easily fusible seal connecting said closures to saidrespective cathode conductors, one of said.

evice comprismembers comprising an extensible section arid externalmeans for exerting traction upon said cathode.

14. An electrical discharge device comprising a cylindrical anode, arod-like cathode located therein, electric terminals for said cathode,

closures including an insulating sec tion sealed between the ends ofsaid anode and said terminals, one of said closures being provided withan extensible section and traction-upon said-cathode, to maintain saidcathode taut when expanded at operating temperatures.

device for exerting 15. In combination, an electrical device Icomprising av metallic casing, an electrode supported 1n the casing, aseal mounted on the caslng, said seal including a vitreous sleeve, meansconnecting said electrode and seal,

said means including a flexible member.

16. In combination, an electrical device comprising a' casing, anelectrode rigidly mounted within the casing, a seal including avitreous'portion, associated with said 'cas- 'mg and electrode, m ans connectinthe elec crimped extensible collar.

17. In combination, an electrical device comprismg a metallic casing, anelectrode r gidly mounted within the casing, a seal mounted on saidcasing, said seal including a vitreous sleeve, means connecting saidelectrade and seal, said crimped extensible .collar.

In witness whereof, I have hereunto set my hand this 29th day ofSeptember, 1922.

JOHN H. PAYNE, JR.'

uding a v i cl din a means 11 u g

